In codifying the methods of translation, several writers have formulated maxims that would constrain interpreters to construe their subjects as (more or less) rational speakers of the truth. Such maxims have come to be known as versions of the principle of charity. W. V. O. Quine suggests an empirical, not purely methodological, basis for his version of that principle. Recently, Stephen Stich has criticized Quine's attempt to found the principle of charity in translation on information about the probabilities of various sorts of mistakes. Here 1 defend Quine's approach. These issues have important implications for the supposed a priori status of human rationality.